
using System;
using System.IO;
using System.Collections.Generic;

namespace JinxBot.Controls.CSS
{

    internal class Token
    {
        public int kind;    // token kind
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1823:AvoidUnusedPrivateFields")]
        public int pos;     // token position in the source text (starting at 0)
        public int col;     // token column (starting at 1)
        public int line;    // token line (starting at 1)
        public string val;  // token value
        public Token next;  // ML 2005-03-11 Tokens are kept in linked list
    }

    //-----------------------------------------------------------------------------------
    // Buffer
    //-----------------------------------------------------------------------------------
    internal class Buffer
    {
        public const int EOF = char.MaxValue + 1;
        const int MAX_BUFFER_LENGTH = 64 * 1024; // 64KB
        byte[] buf;         // input buffer
        int bufStart;       // position of first byte in buffer relative to input stream
        int bufLen;         // length of buffer
        int fileLen;        // length of input stream
        int pos;            // current position in buffer
        Stream stream;      // input stream (seekable)
        bool isUserStream;  // was the stream opened by the user?

        public Buffer(Stream s, bool isUserStream)
        {
            stream = s; this.isUserStream = isUserStream;
            fileLen = bufLen = (int)s.Length;
            if (stream.CanSeek && bufLen > MAX_BUFFER_LENGTH) bufLen = MAX_BUFFER_LENGTH;
            buf = new byte[bufLen];
            bufStart = Int32.MaxValue; // nothing in the buffer so far
            Pos = 0; // setup buffer to position 0 (start)
            if (bufLen == fileLen) Close();
        }

        protected Buffer(Buffer b)
        { // called in UTF8Buffer constructor
            buf = b.buf;
            bufStart = b.bufStart;
            bufLen = b.bufLen;
            fileLen = b.fileLen;
            pos = b.pos;
            stream = b.stream;
            b.stream = null;
            isUserStream = b.isUserStream;
        }

        ~Buffer() { Close(); }

        protected void Close()
        {
            if (!isUserStream && stream != null)
            {
                stream.Close();
                stream = null;
            }
        }

        public virtual int Read()
        {
            if (pos < bufLen)
            {
                return buf[pos++];
            }
            else if (Pos < fileLen)
            {
                Pos = Pos; // shift buffer start to Pos
                return buf[pos++];
            }
            else
            {
                return EOF;
            }
        }

        public int Peek()
        {
            int curPos = Pos;
            int ch = Read();
            Pos = curPos;
            return ch;
        }

        public string GetString(int beg, int end)
        {
            int len = end - beg;
            char[] buf = new char[len];
            int oldPos = Pos;
            Pos = beg;
            for (int i = 0; i < len; i++) buf[i] = (char)Read();
            Pos = oldPos;
            return new String(buf);
        }

        public int Pos
        {
            get { return pos + bufStart; }
            set
            {
                if (value < 0) value = 0;
                else if (value > fileLen) value = fileLen;
                if (value >= bufStart && value < bufStart + bufLen)
                { // already in buffer
                    pos = value - bufStart;
                }
                else if (stream != null)
                { // must be swapped in
                    stream.Seek(value, SeekOrigin.Begin);
                    bufLen = stream.Read(buf, 0, buf.Length);
                    bufStart = value; pos = 0;
                }
                else
                {
                    pos = fileLen - bufStart; // make Pos return fileLen
                }
            }
        }
    }

    //-----------------------------------------------------------------------------------
    // UTF8Buffer
    //-----------------------------------------------------------------------------------
    internal class UTF8Buffer : Buffer
    {
        public UTF8Buffer(Buffer b) : base(b) { }

        public override int Read()
        {
            int ch;
            do
            {
                ch = base.Read();
                // until we find a uft8 start (0xxxxxxx or 11xxxxxx)
            } while ((ch >= 128) && ((ch & 0xC0) != 0xC0) && (ch != EOF));
            if (ch < 128 || ch == EOF)
            {
                // nothing to do, first 127 chars are the same in ascii and utf8
                // 0xxxxxxx or end of file character
            }
            else if ((ch & 0xF0) == 0xF0)
            {
                // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
                int c1 = ch & 0x07; ch = base.Read();
                int c2 = ch & 0x3F; ch = base.Read();
                int c3 = ch & 0x3F; ch = base.Read();
                int c4 = ch & 0x3F;
                ch = (((((c1 << 6) | c2) << 6) | c3) << 6) | c4;
            }
            else if ((ch & 0xE0) == 0xE0)
            {
                // 1110xxxx 10xxxxxx 10xxxxxx
                int c1 = ch & 0x0F; ch = base.Read();
                int c2 = ch & 0x3F; ch = base.Read();
                int c3 = ch & 0x3F;
                ch = (((c1 << 6) | c2) << 6) | c3;
            }
            else if ((ch & 0xC0) == 0xC0)
            {
                // 110xxxxx 10xxxxxx
                int c1 = ch & 0x1F; ch = base.Read();
                int c2 = ch & 0x3F;
                ch = (c1 << 6) | c2;
            }
            return ch;
        }
    }

    //-----------------------------------------------------------------------------------
    // Scanner
    //-----------------------------------------------------------------------------------
    internal class Scanner
    {
        const char EOL = '\n';
        const int eofSym = 0; /* pdt */
        const int maxT = 48;
        const int noSym = 48;


        public Buffer buffer; // scanner buffer

        Token t;          // current token
        int ch;           // current input character
        int pos;          // byte position of current character
        int col;          // column number of current character
        int line;         // line number of current character
        int oldEols;      // EOLs that appeared in a comment;
        Dictionary<int, int> start; // maps first token character to start state

        Token tokens;     // list of tokens already peeked (first token is a dummy)
        Token pt;         // current peek token

        char[] tval = new char[128]; // text of current token
        int tlen;         // length of current token

        public Scanner(string fileName)
        {
            try
            {
                Stream stream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);
                buffer = new Buffer(stream, false);
                Init();
            }
            catch (IOException)
            {
                throw new FatalError("Cannot open file " + fileName);
            }
        }

        public Scanner(Stream s)
        {
            buffer = new Buffer(s, true);
            Init();
        }

        void Init()
        {
            pos = -1; line = 1; col = 0;
            oldEols = 0;
            NextCh();
            if (ch == 0xEF)
            { // check optional byte order mark for UTF-8
                NextCh(); int ch1 = ch;
                NextCh(); int ch2 = ch;
                if (ch1 != 0xBB || ch2 != 0xBF)
                {
                    throw new FatalError(String.Format("illegal byte order mark: EF {0,2:X} {1,2:X}", ch1, ch2));
                }
                buffer = new UTF8Buffer(buffer); col = 0;
                NextCh();
            }
            start = new Dictionary<int, int>(128);
            for (int i = 65; i <= 84; ++i) start[i] = 1;
            for (int i = 86; i <= 90; ++i) start[i] = 1;
            for (int i = 95; i <= 95; ++i) start[i] = 1;
            for (int i = 97; i <= 122; ++i) start[i] = 1;
            for (int i = 10; i <= 10; ++i) start[i] = 2;
            for (int i = 13; i <= 13; ++i) start[i] = 2;
            for (int i = 48; i <= 57; ++i) start[i] = 3;
            for (int i = 9; i <= 9; ++i) start[i] = 4;
            for (int i = 11; i <= 12; ++i) start[i] = 4;
            for (int i = 32; i <= 32; ++i) start[i] = 4;
            start[60] = 5;
            start[45] = 48;
            start[39] = 10;
            start[34] = 11;
            start[40] = 12;
            start[41] = 13;
            start[64] = 14;
            start[123] = 15;
            start[59] = 16;
            start[125] = 17;
            start[44] = 18;
            start[43] = 19;
            start[62] = 20;
            start[126] = 49;
            start[42] = 50;
            start[35] = 21;
            start[46] = 22;
            start[91] = 23;
            start[61] = 24;
            start[124] = 26;
            start[36] = 28;
            start[94] = 30;
            start[93] = 33;
            start[58] = 34;
            start[33] = 35;
            start[47] = 45;
            start[85] = 51;
            start[37] = 47;
            start[Buffer.EOF] = -1;

            pt = tokens = new Token();  // first token is a dummy
        }

        void NextCh()
        {
            if (oldEols > 0) { ch = EOL; oldEols--; }
            else
            {
                pos = buffer.Pos;
                ch = buffer.Read(); col++;
                // replace isolated '\r' by '\n' in order to make
                // eol handling uniform across Windows, Unix and Mac
                if (ch == '\r' && buffer.Peek() != '\n') ch = EOL;
                if (ch == EOL) { line++; col = 0; }
            }

        }

        void AddCh()
        {
            if (tlen >= tval.Length)
            {
                char[] newBuf = new char[2 * tval.Length];
                Array.Copy(tval, 0, newBuf, 0, tval.Length);
                tval = newBuf;
            }
            tval[tlen++] = (char)ch;
            NextCh();
        }



        bool Comment0()
        {
            int level = 1, pos0 = pos, line0 = line, col0 = col;
            NextCh();
            if (ch == '*')
            {
                NextCh();
                for (; ; )
                {
                    if (ch == '*')
                    {
                        NextCh();
                        if (ch == '/')
                        {
                            level--;
                            if (level == 0) { oldEols = line - line0; NextCh(); return true; }
                            NextCh();
                        }
                    }
                    else if (ch == Buffer.EOF) return false;
                    else NextCh();
                }
            }
            else
            {
                buffer.Pos = pos0; NextCh(); line = line0; col = col0;
            }
            return false;
        }


        void CheckLiteral()
        {
            switch (t.val)
            {
                case "url": t.kind = 9; break;
                case "all": t.kind = 12; break;
                case "aural": t.kind = 13; break;
                case "braille": t.kind = 14; break;
                case "embossed": t.kind = 15; break;
                case "handheld": t.kind = 16; break;
                case "print": t.kind = 17; break;
                case "projection": t.kind = 18; break;
                case "screen": t.kind = 19; break;
                case "tty": t.kind = 20; break;
                case "tv": t.kind = 21; break;
                case "n": t.kind = 22; break;
                case "-": t.kind = 46; break;
                default: break;
            }
        }

        Token NextToken()
        {
            while (ch == ' ' ||
                ch >= 9 && ch <= 10 || ch == 13 || ch == ' '
            ) NextCh();
            if (ch == '/' && Comment0()) return NextToken();
            t = new Token();
            t.pos = pos; t.col = col; t.line = line;
            int state;
            try { state = start[ch]; }
            catch (KeyNotFoundException) { state = 0; }
            tlen = 0; AddCh();

            switch (state)
            {
                case -1: { t.kind = eofSym; break; } // NextCh already done
                case 0: { t.kind = noSym; break; }   // NextCh already done
                case 1:
                    if (ch == '-' || ch >= '0' && ch <= '9' || ch >= 'A' && ch <= 'Z' || ch == '_' || ch >= 'a' && ch <= 'z') { AddCh(); goto case 1; } else { t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t; }
                case 2: { t.kind = 2; break; }
                case 3: { t.kind = 3; break; }
                case 4: { t.kind = 4; break; }
                case 5:
                    if (ch == '!') { AddCh(); goto case 6; } else { t.kind = noSym; break; }
                case 6:
                    if (ch == '-') { AddCh(); goto case 7; } else { t.kind = noSym; break; }
                case 7:
                    if (ch == '-') { AddCh(); goto case 8; } else { t.kind = noSym; break; }
                case 8: { t.kind = 5; break; }
                case 9: { t.kind = 6; break; }
                case 10: { t.kind = 7; break; }
                case 11: { t.kind = 8; break; }
                case 12: { t.kind = 10; break; }
                case 13: { t.kind = 11; break; }
                case 14: { t.kind = 23; break; }
                case 15: { t.kind = 24; break; }
                case 16: { t.kind = 25; break; }
                case 17: { t.kind = 26; break; }
                case 18: { t.kind = 27; break; }
                case 19: { t.kind = 28; break; }
                case 20: { t.kind = 29; break; }
                case 21: { t.kind = 32; break; }
                case 22: { t.kind = 33; break; }
                case 23: { t.kind = 34; break; }
                case 24: { t.kind = 35; break; }
                case 25: { t.kind = 36; break; }
                case 26:
                    if (ch == '=') { AddCh(); goto case 27; } else { t.kind = noSym; break; }
                case 27: { t.kind = 37; break; }
                case 28:
                    if (ch == '=') { AddCh(); goto case 29; } else { t.kind = noSym; break; }
                case 29: { t.kind = 38; break; }
                case 30:
                    if (ch == '=') { AddCh(); goto case 31; } else { t.kind = noSym; break; }
                case 31: { t.kind = 39; break; }
                case 32: { t.kind = 40; break; }
                case 33: { t.kind = 41; break; }
                case 34: { t.kind = 42; break; }
                case 35:
                    if (ch == 'i') { AddCh(); goto case 36; } else { t.kind = noSym; break; }
                case 36:
                    if (ch == 'm') { AddCh(); goto case 37; } else { t.kind = noSym; break; }
                case 37:
                    if (ch == 'p') { AddCh(); goto case 38; } else { t.kind = noSym; break; }
                case 38:
                    if (ch == 'o') { AddCh(); goto case 39; } else { t.kind = noSym; break; }
                case 39:
                    if (ch == 'r') { AddCh(); goto case 40; } else { t.kind = noSym; break; }
                case 40:
                    if (ch == 't') { AddCh(); goto case 41; } else { t.kind = noSym; break; }
                case 41:
                    if (ch == 'a') { AddCh(); goto case 42; } else { t.kind = noSym; break; }
                case 42:
                    if (ch == 'n') { AddCh(); goto case 43; } else { t.kind = noSym; break; }
                case 43:
                    if (ch == 't') { AddCh(); goto case 44; } else { t.kind = noSym; break; }
                case 44: { t.kind = 43; break; }
                case 45: { t.kind = 44; break; }
                case 46: { t.kind = 45; break; }
                case 47: { t.kind = 47; break; }
                case 48:
                    if (ch >= '0' && ch <= '9' || ch >= 'A' && ch <= 'Z' || ch == '_' || ch >= 'a' && ch <= 'z') { AddCh(); goto case 1; } else if (ch == '-') { AddCh(); goto case 52; } else { t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t; }
                case 49:
                    if (ch == '=') { AddCh(); goto case 25; } else { t.kind = 30; break; }
                case 50:
                    if (ch == '=') { AddCh(); goto case 32; } else { t.kind = 31; break; }
                case 51:
                    if (ch == '-' || ch >= '0' && ch <= '9' || ch >= 'A' && ch <= 'Z' || ch == '_' || ch >= 'a' && ch <= 'z') { AddCh(); goto case 1; } else if (ch == 92) { AddCh(); goto case 46; } else { t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t; }
                case 52:
                    if (ch == '-' || ch >= '0' && ch <= '9' || ch >= 'A' && ch <= 'Z' || ch == '_' || ch >= 'a' && ch <= 'z') { AddCh(); goto case 1; } else if (ch == '>') { AddCh(); goto case 9; } else { t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t; }

            }
            t.val = new String(tval, 0, tlen);
            return t;
        }

        // get the next token (possibly a token already seen during peeking)
        public Token Scan()
        {
            if (tokens.next == null)
            {
                return NextToken();
            }
            else
            {
                pt = tokens = tokens.next;
                return tokens;
            }
        }

        // peek for the next token, ignore pragmas
        public Token Peek()
        {
            if (pt.next == null)
            {
                do
                {
                    pt = pt.next = NextToken();
                } while (pt.kind > maxT); // skip pragmas
            }
            else
            {
                do
                {
                    pt = pt.next;
                } while (pt.kind > maxT);
            }
            return pt;
        }

        // make sure that peeking starts at the current scan position
        public void ResetPeek() { pt = tokens; }

    } // end Scanner

}